1. Field of the Invention
The present invention relates to a magnetic disk drive device.
2. Related Art
A magnetic disk drive device as illustrated in FIGS. 6 and 7 has been known.
The magnetic disk drive device illustrated is of the so-called central shaft fixing type. For simplicity of illustration, only the right half of the structure with respect to the center line is illustrated.
In FIGS. 6 and 7, a central shaft portion 1a integral with a frame 1 is extended at the central part of the frame. A stator core 3 is fastened to the tubular portion of the frame 1, close to the central shaft portion 1a thereof. A coil 4 is wound about the stator core 3. Bearings 5, axially separated, are fit into a space between the central shaft portion 1a of the frame 1 and a hub 7 in a manner such that the inner rings of the bearings are in contact with the outer surface of the central shaft portion 1a and the outer rings of the bearings 5 are in contact with the inner wall of the hub 7. The hub 7 is disposed so as to cover the upper side and the outer side of the combination of the stator core 3 and the coil 4. A magnetic disk, not illustrated, is placed on the hub 7 in a state that the hub is inserted into the center hole of the magnetic disk. A ring-like drive magnet 8 is fastened to the inner wall of the hub, which confronts with the stator core 3.
A hole 1b is formed in the portion of the frame 1, right under the coil 4. A cutout portion 1c is formed in the bottom of the frame including the hole 1b. Coil terminal wires, not shown, are led from the coil 4. Within the frame 1 the coil terminal wires are connected to lead wires 9. The lead wires 9 are fixed within the hole 1b by means of adhesive 11. The lead wires 9 are further fixed within the cutout portion 1c by means of a clamp member 13. The lead wires 9 are connected to a power supply means, located outside the motor. A drive power is fed from the power supply means through the lead wires 9 to the coil 4, which in turn turn rotates the hub 7 with a magnetic disk set thereto.
In FIG. 6, reference numeral 10 denotes a connector, and 12, a sealing means.
In the magnetic disk drive device that is described above, the lead wires 9 are used for supplying an electric power to the coil 4. The magnetic disk drive device of the type in which a flexible printed circuit is used for the same purpose is also known.
This type of the magnetic disk drive device is shown in FIGS. 8 and 9. In those figures, like reference numerals are used for designating like portions in FIGS. 6 and 7. Description of those like portions is omitted.
In FIGS. 8 and 9, a cutout portion 1d, larger than the cutout portion 1c, is formed in the bottom of the frame 1. A flexible printed circuit 16 is bonded within the cutout portion 1d. The flexible printed circuit 16, extended outside the motor, is constructed such that a conductor pattern 16a is formed on the base made of insulating material, and a cover of insulating material is layered on the conductor pattern 16a. Coil terminal wires 14 are led out of the motor, through the hole 1b of the frame 1, and soldered to soldering lands 15, exposed or not covered with the cover of the flexible printed circuit 16.
A drive power is supplied from the power supply means to the coil 4 of the motor, by way of a route of the conductor pattern 16a and the soldering lands 15 of the flexible printed circuit 16, and the coil terminal wires 14.
The conventional magnetic disk drive devices as described above have the following problems.
In the magnetic disk drive device of the type in which the drive power is supplied to the motor by the lead wires 9, the coil terminal wires and the lead wires 9 must be connected within the frame 1. Accordingly, the wire connection work is difficult. The result of the wire connection is poor in reliability.
In the magnetic disk drive device of the type in which the flexible printed circuit 16 is used for supplying the motor drive power, the wire connection work is easy, and the result of the wire connection is reliable. However, the flexible printed circuit 16 is costly, and fragile. When receiving an impact, it is easily broken, resulting in disconnection of the printed conductors. The flexible printed circuit 16 is flexible in the axial direction of the motor (vertical direction in the drawing), but is inflexible in the direction of an arrow A in FIG. 9. The flexible printed circuit cannot be moved, even slightly, in the same direction. This limits the layout freedom of the device. Namely, the problems of both types of devices are different from each other.